UI Weed Scientist Asks the Question:

Published online: May 09, 2000

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Can Growers Who Wait Out sugarbeet Planting Outwit Weeds?

TWIN FALLS, Idaho-In the Magic Valley, sugarbeet producers generally plant in mid-April-just in time for kochia, lambsquarters, nightshade and wild oats to begin emerging alongside their beet seedlings. Depending on their density, those weedy thugs can pummel 10 to 100 percent of the yields right out of the crop.

Don Morishita, University of Idaho extension weed scientist is experimenting with an integrated weed management approach that may allow the crop to throw the first punch. In a preliminary study this year, he is evaluating the impacts on weed populations of five different planting times scheduled at one-week intervals between April 18 and May 16. Morishita is sowing the beets into plots treated with the nonselective herbicide glyphosate, or Roundup, to level weed competitors before the crop emerges-and thereby level the playing field for the young beets.

He expects the study to confirm what growers have long known: delaying planting diminishes yields. "But if we can reduce weed-control costs, maybe we can offset that yield penalty," he says.

John Gallian, UI extension sugarbeet specialist, says Idaho sugarbeet growers would need "compelling reasons" to delay planting. Typically, they plant as soon as they can because they've learned that delays cost them one ton of yield per week. "The best growers are always ready to plant during an early-season window of opportunity," he says. "It's worth the risk of frost injury." In addition, delaying planting exacerbates such root diseases as rhizomania, says Gallian. Giving the plant a head start before disease organisms warm up to their root-deforming tasks "greatly reduces the potential disease loss."

Morishita's study is being conducted at the Kimberly Research and Extension Center.